class_docstr: Retain every `step` features (beginning with 0).
  
  If `step < 1`, then no features are selected.
class_docstr_tok: ["Retain","every","`","step","`","features","(","beginning","with","0",")",".","If","`","step","<","1","`",",","then","no","features","are","selected","."]
code: def _get_support_mask(self):
      mask = np.zeros(self.n_features_in_, dtype=bool)
      if self.step >= 1:
          mask[:: self.step] = True
      return mask
  
file_path: scikit-learn/sklearn/feature_selection/tests/test_base.py
imports: import numpy
  import pytest
  from numpy.testing import assert_array_equal
  from sklearn.base import BaseEstimator
  from sklearn.feature_selection._base import SelectorMixin
  from sklearn.utils.fixes import CSC_CONTAINERS
label_desc: Use image node_id 3 for calling the StepSelector obj's underlying member method code with example usage: obj._get_support_mask() and returns: mask